Auger



' UNITED STATES PATENT OFFICE.

REJENNINGS, OF DEEP RIVER', CONNECTICUT.

AUGER.

Specicaton forming part of Letters Patent No. 12,8118, vdated January30, 1855; Ressued October 3, 1865, No. 2,081.

To all lLoh-0m t may concern.'

Be it known that I, RUSSELL JnNNINGs, of Deep River, in the county ofMiddlesex and State of Connecticut, have invented a new and usefulImprovement in the Double- Twist Augers, of which the following is afull, clear, and exact description,- reference being had to theaccompanying drawing, which forms part of this specification and inwhich- Figure l represents a side elevation of my improved double twistauger, and Fig. 2 is an end view of the same.

Angers as usually constructed are composed of two members, the cut-tingbit and the pod, the latter acting to discharge the chips separated bythe former. The cutting bit in double-twist angers has two radialcutting edges or fioor lips extending at right angles to the aXis of theauger from the pintle or screw to the periphery of the twisted pod. Eachfloor lip is furnished at its outer corner with a spur or cutter whichprojecting, in the direction ofthe axis of the auger, beyond its cuttingedge, cuts round the periphery ofthe cylinder ofwvpod removed by thefloor lips. The spur thus described being at the outer co-rner of thefioor lip acts in conjunction with it', and augers thus constructed arevery defective; first, because the spur is projected from the thinnestpart of the Hoor lip and to be useful as a cutter it must be made toothin for durability and strength, hence it together with the portion ofthe cutting edge of the floor lip from which it is projected arecontinually liable to break off in using and this liability to break isso great that augers thus constructed are considered unfit for boringhard wood. This contiguity of the cutting edge of the floor lip and spuris also objectionable because when the former is broken by boringagainst a nail or other hard substance, thereis no material in reserveto allow a new cut" ting edge to be filed further back on the lip andthe instrument becomes useless. Another difficulty arising from thiscontiguity of the cutting edge of the floor lip and the spur,;.is thatwhen the former is cuttin a chip, the latter acts to cut round the e geof the neXt succeeding chip in exact conjunction with the former, hence,each interferes with the action of the other, the fibers o-f the woodare torn as the bit enters, and the hole is not bored' smoothly.

improved double-twist auger isdesigned to overcome these objections, andmy improvement consists in constructing the cutting bit in such mannerthat the Hoor lip and ther spur, instead of acting in conjunction, actseparately and independently of each other. The instrument asrepresented in the drawing is constructed with a double twisted pod Aand two floor lips B, B, the latter project beyond the positions inwhich they have heretofore been placed, and the spur a, instead of beingsituated at the outer front corner of the cutting edge of t-he floor lipwhere the latter from its necessary thinness is weakest, is projectedfrom its hinder part or heel where it is thickest and strongest. By thischange in the relative positions of the cutting edge of the floor lipand the spur, I effect. a new relationship between them so that the onein acting does not interfere with the operation of the other. and aninstrument is obtained which is strong and durable, while at the sametime it requires less power to operate it t-han the common auger,produces a smoother hole, and will bore faster without danger ofbreakage. These advantages ensue, first, because the spur being situatedat some distance'behind the cutting edge of the floor lip does notnecessarily act to cut throughout its entire length and hence its rootcan be made larger than is possible in the ordinary method ofconstructing double twist augers, where its increase in size at theouter corner of the floor lip would impede the action of the instrument.Secondly, as the spur is projected from the strongest part of the lip,it is not liable to break with the strain and carry with it a portion ofthe floor lip. Thirdly, the instrument is much more durable because asthe floor lip is filed away, a suflicient quantity of material is inreserve to form a new cutting edge, and as the spur can be made heavierand stronger, it also is of sufficient size to admit of a considerableamount of filing before its strength is materially impaired. Theefliciency of the instrument and the smoothness of the hole bored arethe necessary results of this improved construction, first, because thewoodupon which the spur is acting is not disturbed by the floor lip andremains firm both before and behind the spur which thus cutsv smoothlyround the edge of the chip to be removed by the succeeding floor lip;secondly because the chips removed by the floor lip being undisturbed bythe action of the spur pass freely out of the hole as fast as they arecut thus preventing the choking of the pod. The double twist auger thusconstructed becomes an eflcient instrument for boring hard woods, eitheracross or enclwise with the grain, for .which purpose the ordinarydouble twist augers are almost useless. It may be constructed with orwithout the side lip projecting upward from the periphery of the floorlip,A but I prefer to construct it as represented in the accompanyingdrawing, without this adelition, which is useless when the spur performsits work efficiently, as it must do in my auger.

VVhatI claim as my invention and desire to secure by Letters Patent is-wSo constructing the cutting edges of a double twist auger or auger bit,that the vertical scores shall follow the chisel; z'. e. so that thecutting edges of scores and chisel shall never intersect the wormorheliX of the shaft at the same point.

Y RUSSELL JENNiNGs.

Vitnesses:

CHARLES W. SNOW, EGBERT C. PRATT.

[FIRST PRINTED 1913.]

